Thomas pownall ford



(No Model.)

T. P. FORD.

HYDRAULIC LIFT.

No. 387,407. Patented Aug. 7, 1888'.

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THOMAS POWNALL FORD, OF LONDON, ENGLAND, ASSIGNOR TO THE AMERICANELEVATOR COMPANY, OF SAME PLACE.

HYDRAULIC LIFT.

SPECIFICATION forming part of Letters Patent No. 387,407, dated August7, 1888.

Application filed January 5, 1888.

To aZZ whom it may concern:

Be itknown that I, THOMAS POWNALL FORD, at present residing at 4 QueenVictoria Street, in the city of London, England, engineer,have inventednew and useful Improvements in Hydraulic Lifts,of which the following isa full, clear, and exact description.

My invention relates to that kind of 11ydraulic lift in which the cageis suspended by a chain or rope passing round an overhead sheave andunder a sheave carried at the upper end of the rod of a piston workingin a vertical cylinder with a column of water above and below it,whereby the lift is actuated.

The invention re1ates,first, to the valve-gear for controlling theadmission of the water to the main cylinder and its circulation from oneend of said cylinder to the other; and it has for its object to enableplug'or slide valves to be used and at the same time prevent leakageofthc water owing to grit preventing the valves being properly'seated.

The invention consists in the combination, with valves, of the plug orsliding type sustaining the bulk of the pressure from the supply andcontrolling the circulation of water from one end of the main cylinderto the other, of an auxiliary cup-leather valve which is operatedconcurrently with and by the same hand rope-gear as the main valves.Cup'leather valves, which are not liable to leakage like metal valves,cannot, however, be used to the same advantage if exposed to highpressure, (say seven hundred pounds per square inch,) such as it isproposed to use in this lift, as they are liable to be forced throughand be out in passing over the openings in their seats. In thecombination of my invention the cupleather valveis exposed when passingover the ports in its seat only to a very diminished pressure, which isinsufficient to injure the cup-leather valve, the office of this valvebeing merely to arrest any leakage that might occur at the main valveswhen all the valves are closed.

The invention has, secondly, for its object to prevent the applicationof pressure to the under side of the piston in consequence of leakage,as well as to compensate for the difference of area of the two ends ofthe main cyl- Serial No. 259,888. (No model.)

inder (due to the displacement of the pistonrod) by admittinglow-pressure water to make up the deficiency when the water iscirculated from the upper to the lower end of the cylinder.

My invention relates, thirdly, to an automatic regulator for checkingthe flow of water both on the ascent of the main cylinder under a lightload or on itsdescent under a heavy load.

Reference is to be had to the accompanying drawings, forming part ofthis specification, wherein- Figure 1 is an elevation, partly insection, of the main-cylinder, circulating-pipe, and valvegear of ahydraulic lift of the class to which my invention relates. Fig. 2 isvertical section through the cup-leather valve scp arately. Fig. 3 is avertical section of the regulator.

The same letters of reference indicate the same parts in all thefigures.

The main valves A B, which may be of the conical-plug form, comprise avalve, A, con trolling the water from the supply to what I term acirculation-chamber, C, and a similar valve, B, controlling the passageof water from the circulation-chamber C to the circulating-pipe D, thatleads therefrom to the upper end of the main cylinder E, these twovalves A B being operated by gear from the hand-wheel rope passingthrough the car. F is a cup-leather piston-valve working within thecirculation-chamber as a cylinder and controlling circulation, orby-pass orifices g, the said valve being operated simultaneously withvalves A and B through rack and pinion or other gear.

The valvegear shown consists of levers a b, connected with the stems ofvalves A 13, respectively, both levers being connected with the samerack-rod I, gearing with a pinion, t, on the axis of the pulley K, overwhich runs the hand-rope. The lever a is connected to the stem of valveA by a pin-and-slot connection, a, which permits of motion of the levertoward the valve A, although the latter has closed on its seat. Thelever b is abell-crank lever and is connected with the stem of valve Bthrough a link, 12, the center of motion, 1),

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of the lever being opposite the end of the valve, so that the latterwill be closed on the leverarm link and valve-spindle coming into line,and will be opened by angular motion of the lever either way from theposition shown. The cup-leather piston'valve F is carried on aspindle,f, having racktecth on its upperend and gearing with a pinion,f, on the same axis with pinion i.

The operation is such that when the valve A from the supply is openedthe valve .13 is also opened to admit water to the upper end of the maincylinder E, the cup lcather valve F being then raised wholly above theorifices or ports g,whieh it controls, and when by motion in theopposite direction the valves A B are closed and the valve B aloneopened by the continued motion of levcrb the cup-leather valve will bemoved to the position shown in Fig. 2, between the two sets of by-passor circulation ports 9 g, which permit the water to circulate from theupper end of the main cylinder through pipe I), chamber 0, by-pass y topipe H, leading to the lower end of said cylinder.

The invention consists, secondly, in keeping the exhaust-pipe Hconnected to the lower end of the main cylinder always open instead ofelosin g it by a valve, as heretofore, so that were leakage past thevalves or main piston to occur when the cage is landed no pressure canbe generated against the lower side of the main piston, which cannot,consequently, rise and throw the sheave off the ropes. The exhaustpipe Hdischarges into an open tank, L, (as near as possible at the level ofthe bottom end of the cylinder 1G,) into which the mouth of the pipe Hdips below the level of water retained therein, so that the deficiencyin volume of the circulating water will be made up by water forced backby atmospheric pressure through the exhaust-pipe to the main cylinder.

The action of the regulator which forms the subject of the thirdimprovei'nent is d ac to the inertia of the column of water itself. Theregulator consists in a plunger-valvc,l\ Fig. 3, fitted to work in acylinder in line with the column of water in the pipe D to be regulated,so that the latter will impinge directly against the end oftheplnngenvalve. The cylinder is formed with by'pass passage 0 P,communicating with ports 0 1), controlled by the plunger, which acts asa balance-valve, controlling the flow of water transversely across thecylinder from port 0 to port ,1 orvice versa. The plunger is held (by aweighted bent lever, B R, working on an axis, Q, or other equivalentcontrivance) in its normal or mid position, so as to give a full passageto the water; but on the water striking the end of the piston with avelocity exceeding a predetermined limit the weight will be overcome andthe plunger moved so as to check the flow of water at the ports op, theaction being similar in whichever dircction the water is flowing. InFig. 3 the water is supposed to be flowing in the direction of thearrow.

The motion of the plunger-valve would be limited by snitablcstops, sothat it shall never out off entirely the passage of the water. In theexample shown the stops are formed by the arm it of the weighted leverabutting against the top and bottom of the slot in the casting in whichit moves.

Having now particularly described and ascertained the nature of the saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- 1. In a hydraulic lift of the type specified, theCOIllblllEltlOl], with water supply and cir' culation valves A B of theplug or sliding type, and the chamber 0, connected with the maincylinder, as described, of a cup-leather piston-valve, F, controllingthe passage from chamber 0 to the lower end of the main cylinder andacting in conjunction with the valves A B as a second seal to preventleakage, both sets of valves being operated by the same gear,substantially as specified.

2. The combination, with the valves A, B, and F, of the rack-and-piniongca' and levers for operating such valves, and consisting ofthe pistonrack-rod f, pinionsf and i, rack-rod I, and levers a I), connected torack-rod I and to the stems of valves A B, substantially as shown anddescribed.

3. In a hydraulic lift, a doubleaeting regulator for checking both thesupply and circulation of the water, and consisting of a plungervalve,N, working in a cylinder interposed in line axially of the column ofwater and provided with by-pass passages and ports 0 0 P 1), acrosswhich the valve works, said valve being combined with a weightedelbow-lever, R 1%, whereby the valve is held against the momentum ol'the water.

The foregoing specification of my improvements in hydraulic lifts signedby me.

THOMAS POWNALL FORD.

Witnesses:

G. F. WARREN,

17 Gracechm'ch Street, London. T. W. KENNARD,

53 Chancery Lane, London.

